Application of electrical resistivity tomography methods for Bitumen detection: A case study from Andika, Iran

detecting and characterizing natural bitumen deposits in Andika County, located in Khuzestan Province in southwestern Iran. This research employs a comprehensive approach combining geophysical surveys with geological data for mapping subsurface bitumen accumulations.The methodology involves conducting five ERT traverses using a dipole-dipole array configuration, with profiles extending ۱۰۵ meters in length and reaching depths of approximately ۱۵.۵ meters. Data processing and inversion employed smoothness-constrained least-squares techniques.Results showed a consistent correlation between high-resistivity zones and bitumen-rich areas. Resistivity values in the range of ۷۰۰ to ۱۸۰۰ ohm-meters were strongly associated with bitumen deposits, with the highest concentrations exhibiting resistivities above ۱۲۵۰ ohm-meters. Areas with resistivities between ۵۰۰ to ۱۰۰۰ ohm-meters often indicated bitumen mixed with other sediments. To validate the ERT results, a borehole was drilled at ۵۲ meters along the fourth traverse. The borehole report confirmed high-concentration bitumen layers at depths corresponding to high-resistivity zones in the ERT data, particularly between ۳.۴-۶.۲ meters and ۷-۸.۵ meters. Horizontal cross-sections at different depths (۶, ۱۰, and ۱۳ meters) were analyzed to understand the lateral continuity of bitumen deposits across the study area.This study also identified the role of geological structures, with fractured zones serving as conduits for bitumen migration, while clay and marl layers acted as barriers. This research demonstrates the effectiveness of integrating ERT with borehole data for accurate mapping and characterization of natural bitumen reserves, providing a strong framework for future exploration efforts and promoting environmentally responsible resource management in bitumen-rich regions

کلیدواژه ها:

Natural Bitumen ، Electrical Resistivity Tomography (ERT) ، Dipole-Dipole ، Two-Dimensional Geoelectric Modeling Andika.